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The COVID-19 pandemic has shoved most of the countries to implement restrictions for transportation and all other social activities to minimize spread of disease to the people. India is the second most populated country in the world which has implemented a historical complete lockdown throughout the country from the last week of March to April 2020 with an extension up to the first week of May 2020. This lockdown has slowed down the pollution levels in most of the cities in India within the first few weeks of the lockdown. In this view, the present study discusses the air quality scenario of Chennai, one of the megacities of India, scientifically. With the aid of air quality data of the Tamil Nadu Pollution Control Board, India, for five parameters such as PM 2.5 and P.M 10, sulphur dioxide, nitrogen dioxide and air quality index, the authors correlated the pre-during-post lockdown air quality of Adyar, Chennai. The results indicated that the concentrations of particulate matter reduced to about 50 � 80 % during the lockdown compared to pre-lockdown. The concentrations of sulphur dioxide and nitrogen dioxide were decreased to 50% and 20%, respectively, within the first week of lockdown. Further the data were compared with the pollution data for the past two years (2018 and 2019). The present study gives insight on the reduction of pollution in proportion to the temporary control of pollution source at particular interval could rejuvenate the environment.

Purpose Development of thin film sensors with pH function for noninvasive real-time monitoring of spoilage of packed seafood such as fish, crab and shrimp are described in this study. It is also the purpose of this study to enhance the leaching resistance of the sensors by using a suitable strategy and to quantitatively correlate the sensor’s halochromism with the total volatile amine. Design/methodology/approach To prepare halochromic sensors with better leaching resistance, biocompatible materials such as starch, agar, polyvinyl alcohol and cellulose acetate along with a halochromic dye were used to prepare the thin film sensors. These thin films were evaluated for monitoring the spoilage of packed seafood at room temperature, 4°C and −2°C up to 30 days. The halochromic sensors were characterized using UV-visible and FT-IR spectroscopy. Findings CIELab analyses of the halochromism of the thin film sensors revealed that the color changes exhibited by the sensors in response to the spoilage of seafood are visually distinguishable. Further, the halochromic response of the thin films was directly proportional to the amount of total volatile base nitrogen that evolved from the packed seafood. Excellent leaching resistance was observed for the developed thin film sensors. The halochromic property of the sensors is reversible and thus the sensors are recyclable. Besides, the thin film sensors exhibited significant biodegradability. Originality/value This study provides insights for use of different biocompatible polymers for obtaining enhanced leaching resistance in halochromic sensors. Further, the color changes exhibited by the sensors are in line with the total volatile amines evolved from the packed seafood. These results highlight the importance of the developed halochromic thin film sensors for real-time monitoring of the spoilage of packed seafood.

Development of a biodegradable and recyclable halochromic biosensor for monitoring spoilage of packaged seer fish is described in this study. The biosensor was prepared completely from materials of natural origin. The sensor was characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and image processing by CIELab. The biosensor indicated spoilage of fish by exhibiting a visible color change from brownish pink to yellowish green. The results of the biodegradability test indicated that the developed sensors decompose at the rate of 60–70% in 2 weeks. This biosensor can be recycled at least six times. It was also estimated that the cost for one biosensor per package was approximately 2 cents. Thus, the biosensor developed in this study is economical, biodegradable, and efficient in monitoring spoilage of packaged fishes. Hence, this economical biosensor can easily be adopted by retail sellers and exporters. The biosensor developed in this study is promising for monitoring spoilage of packaged fishes in retail markets.

Purpose The present study aims to describe the development of halochromic thin film sensors using mixed indicator dyes for monitoring the spoilage of packed seer fish. Design/methodology/approach Thin film was prepared using renewable polysaccharide incorporated with mixed indicator dyes. The thin film was characterized using ultraviolet visible and Fourier transform-infrared spectroscopy. The characteristics of the thin film were studied by analyzing the CIELAB and Red Green Blue values and biodegradability. The thin films were evaluated for real-time monitoring of the spoilage of packed seer fish. Findings The thin film sensors were found to exhibit excellent halochromism. The color changes were visible and distinguishable. The sensors responded efficiently for real-time monitoring of spoilage of fish by showing unique color changes. Originality/value This study provides promising mixed indicator that exhibits different colors in the alkaline pH. Also the present study reveals a potential combination of materials for preparation of halochromic sensors that can be used for monitoring the spoilage of packed seer fish in real time.

Purpose This study aims to describe the development of a battery-operated portable colorimeter for on-site determination of water quality in aquaculture. Design/methodology/approach A simple and economical colorimeter is built using light sources of different wavelength and a light-dependent resistor combined with an electrical circuit. The whole system was fabricated as to fit into the pocket or palm for easy handling. The developed portable colorimeter was calibrated for estimation of nitrite. Further, the performance of developed portable colorimeters was compared with the commercially available colorimeter. Findings Three colorimeters with different light sources were developed and calibrated for determination of nitrite in water. Among them, colorimeter with yellow light source exhibited higher potential for determination of nitrite in the range of 0.5–3.5 ppm. Further, the results of the developed colorimeter are comparable with the commercial colorimeter. Originality/value The portable colorimeter developed in this study exhibits potential for determination of nitrite in aquaculture. Determination of nitrite at low concentrations is important for assessing the quality of culture as well as wastewater in aquaculture industry. The accuracy, portable nature, economy and simple operation of these portable colorimeters offer opportunity for on-site determination of water quality parameters in aquaculture.

The present study describes the application of Tunbergia fragrans extract for inhibition of mild steel corrosion in hydrochloric acid medium. At first the inhibitor was extracted from the plant using ethanol to obtain the crude extract. This crude extract was added into the pickling solution of hydrochloric acid at different concentrations. Then the mild steel corrosion inhibition efficiency of the inhibitor was determined using weight loss method and electrochemical analysis. The results indicated that the plant extract inhibits the corrosion of the mild steel upto 81% in 1 M HCl. The weight loss data obeyed the Langmuir adsorption isotherm which suggested for predominant physical adsorption. Further, the interaction between the inhibitor and the mild steel surface were observed using scanning electron microscopy coupled with energy dispersive spectrum.

Development of halochromic thin film sensors for monitoring the degree of spoilage of packaged seer fish is described in this study. Three halochromic thin film sensors were prepared by combining a halochromic dye with starch/potato dextrose agar, polyvinyl alcohol, and cellulose acetate and characterized using Fourier-transform infrared spectroscopy. The halochromic sensors were tested for monitoring spoilage of packaged seer fish at ambient temperature, refrigerated, and frozen conditions. The halochromic response of the thin film sensors was evaluated by image processing and color measurements such as CIE Lab and RGB value determinations. All the three thin film sensors exhibited excellent color changes in proportion with the spoilage of the packed seer fish. These halochromic thin film sensors are useful for real-time monitoring of spoilage of packed seafood.

The present study describes biosynthesis of copper nanoparticles using the Borreria hispida (Linn.) plant extract. At first, the crude extract was extracted from the dried whole plant Borreria hispida (Linn.) using methanol. Then the extract was used to synthesis copper nanoparticles. The morphology and elemental composition of the synthesized copper nanoparticles were observed using scanning electron microscopy coupled with energy dispersive spectrum. The copper nanoparticles were having size between 84 and 158 nm. The X-ray diffraction pattern confirmed the presence of metallic copper nanoparticles and absence of copper oxide. Further the copper nanoparticles exhibited significant anti-oxidant activity.

The frequent application of synthetic insecticides creates resistance among insects, including mosquitoes, and causes environmental pollution and health issues. The current work aim at assessing the possibilities to produce and characterize the titanium dioxide (TiO2) nanoparticles (TiO2 NPs) mediated through the aqueous leaf extract of Pouteria campechiana, and their larvicidal and pupicidal activities against Aedes aegypti. The attained results showed that the aqueous leaf extract of P. campechiana had the efficiency to fabricate TiO2 NPs from TiO2. Under the UV-vis spectrum analysis, a sharp peak was recorded at 320 nm, which indicated the production of TiO2 NPs by the plant extract. The SEM analysis revealed that the synthesized TiO2 NPs were spherical, and 5 dissimilar diffractions were detected in the XRD spectrum analysis related to the TiO2 NPs. In FTIR analysis, a prominent peak was found at 1052.41 cm−1, corresponding to alcohol, and confirmed metal reduction. In the EDX analysis, there was a signal of around 58.44%, confirming the decrease in Ti from TiO2 NPs, and the remaining percentages were Ca, Al, and Mg. About 900 μg mL−1 of TiO2 NPs had excellent lethal activity against various larvae and pupa stages of Ae. aegypti. The attained results showed that the P. campechiana aqueous leaf extract could reduce TiO2 into TiO2 NPs and could be considered a mosquito control agent. Furthermore, this is the initial report about the aqueous leaf extract of P. campechiana effectively synthesizing the TiO2 NPs with anti-mosquito activity.

Rivers are the most significant natural resources that afford outstanding habitation and nourishment for numerous living organisms. Urbanization and industrialization pollute rivers rendering their water unhealthy for consumption. Hence, this work was designed to find a potential native pollutant removing algae from polluted water. The physicochemical properties of the tested river water such as Electric Conductivity (EC), turbidity, total hardness, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ca, SO2-, and NH3, NO3, NO2, PO4, Mg, F- and Cl- contents were not within the permissible limits. Lab-scale and field-based phycoremediation treatments with the indigenous native microalgal species, Chlorella sp. from the Thirumanimutharu river water sample were set up for 15 days with three different (Group I, II, and III) biomass densities (4 × 104, 8 × 104, and 12 × 104 cells mL-1). Group III of both the lab-scale and field based treatments showed the maximum reduction in the physicochemical parameters compared to the other groups. Further, the group III of the field based study showed an extensive reduction in BOD (34.51%), COD (32.53%), NO3, NO2, free NH3 (100%) and increased dissolved oxygen (DO) (88.47%) compared to the lab scale study. In addition, the trace elements were also reduced significantly. The pollutant absorbing active functional moieties (O-H, CO, and CN) found on Chlorella sp. had been confirmed by Fourier-Transform Infrared Spectroscopy (FTIR) analysis. In the Scanning Electron Microscope (SEM) study, significant morphological changes on the surface of the treated Chlorella sp. were noticed compared with the untreated Chlorella sp. biomass, which also confirmed the absorption of the pollutants during treatment. Department of Science & Technology (India) SR/FIST/LSI-673/2016; King Saud University RSP-2021/5 info:eu-repo/semantics/publishedVersion

Electrospinning and post-spun conformations of hydrophobic poly(α-amino acid)s are described in this study. The poly(α-amino acid)s, poly(Gly), poly(l-Ala), poly(l-Val), and poly(l-Leu) were synthesized via corresponding N-carboxy-α-amino acid anhydrides. The average molecular weight and degree of polymerization of these polymers were determined by N-terminus labeling using 2,4-dinitrofluorobenzene and by viscometry in the case of poly(Gly). These poly(α-amino acid)s were electrospun from trifluoroacetic acid or trifluoroacetic acid/dichloromethane solutions. The FT-IR spectroscopy and wide-angle X-ray diffraction indicated that the electrospun poly(l-Ala) and poly(l-Leu) fibers predominantly adopts α-helical structure, whereas poly(l-Val) and poly(Gly) fibers exhibited mainly β-strand and random coil structures, respectively.

The excess load of organic and inorganic pollutants in Chanramkudi Lake water creates eutrophication resulting from excess growth and spreading of water hyacinth and bad odor and provides favorable circumstances for the survival of disease spreading insect vectors and possibilities of disease occurrence. The results showed that the suitable temperature and residence time for the conversion of dried biomass of water hyacinth into useful biochar was 350 °C and 60 min, respectively, and 33.6% of water hyacinth biochar (WHBC) at stable organic content basis of 49.2% was produced. The WHBC produced under this condition had physicochemical properties such as 389.8 mmol kg−1 of CEC (Cation Exchange Capacity), 69.1 of C/N, 68.2 of C, 234.7 mg kg−1 of total P, 19.7% of ash, and 59.4% of volatiles with pH 7.9. The metal adsorbing competence of this WHBC with and without A. niger was tested with various concentrations (250, 500, 750, and 1000 mg L−1) of various metal (Cd, Cr, and Pb) containing solutions. The WHBC with A. niger amalgamation (15:3 g) effectively adsorbed the metals even at 1000 mg L-1 such as Cr (91.5%), Cd (95.6%), and Pb (93.9%) than individually. The metals were adsorbed and immobilized in the pores of WHBC and the outer layer of the cell wall of A. niger was observed under SEM analysis with various scaling (50, 100, and 150 µm). Further, the pollutant adsorbing functional groups were found in both WHBC and dead mycelia biomass of A. niger through FTIR analysis. The attained results concluded that the biochar produced from challenging water hyacinth could adsorb and minimize the pollutants with an amalgamation of A. niger. Significantly, more volume (33.6%) of biochar can be derived from water hyacinth. Furthermore, WHBC and A. niger are easily cultivable. Thus, it could be preferably useful for removing real-world organic and inorganic pollutants from polluted water.

As a highly effective nanocomposite for hydrothermal liquefaction (HTL) of microalgae, the recycled biochar synthesized from Spirulina platensis and impregnated into CeO2 has been demonstrated. The order of in situ > ex situ > biochar nanocomposites for higher bio-oil. The highest bio-oil conversion of 33% was achieved at the optimum temperature of 250 °C. The use of the biochar nanocomposite also resulted in a decrease in the oxygen and nitrogen content of the bio-oil and an increase in its heating value, which was found to be high at 35.64 MJ/kg. With the inclusion of the in situ biochar nanocomposite, energy recovery was increased by up to 65.34%. The current study has shown that low biochar nanocomposite concentrations (0.20 g), low temperature (250 °C), and short residence time (30 min) are essential for improved bio-oil yield and quality of bio-oil.

In this study, we present a highly efficient and economical solution called as 'in situ hydrogenation' for preparation of highly conductive thin film electrode based on silver nanodendrites. The silver nanodendrite (AgND)/cellulose acetate (CA) thin film electrodes exhibited sheet resistance ranging from 0.32ohm/sq to 122.1ohm/sq which could be controlled by changing the concentration of both silver and polymer. In addition, these electrodes exhibited outstanding toughness during the bending test. Further, these thin film electrodes have great potential for scale-up with an average weight of 3mg/cm2 and can be also combined with active nanomaterials such as multiwalled carbon nanotubes (MWCNTs) to fabricate AgND/CA/MWCNTs thin film for high-performance flexible supercapacitor electrode. The AgND/CA/MWCNTs electrodes exhibited a maximum specific capacitance of 237F/g at a current density of 0.3A/g. After 1000 cycles, the AgND/MWCNT/CA exhibited a decrease of 16.0% of specific capacitance.

The inhibition potential of some expired waste pharmaceutical drugs, namely cefpodoxime (CF), levofloxacin (LV), ofloxacin (OX) and linezolid (LZ) on cast iron corrosion in 1 M HCl has been tested for the first time by chemical (weight loss) and electrochemical (Tafel polarization and impedance spectroscopy) methods. At a constant acid concentration (1 M HCl), the inhibition efficiency (IE%) increased with the increase of the inhibitors’ concentration. At optimum inhibitor concentration, the CF exhibited the highest inhibition efficiency (95.2%). Inhibitors were adsorbed on the cast iron surface through the Langmuir adsorption isotherm at all concentrations and temperatures studied. Antagonism and synergism arising between the halide ions and the inhibitors were also explained. Thermodynamic parameters have been calculated and are discussed. Tafel polarization curves pointed to all inhibitors acting as mixed-type. Corrosion inhibition properties of the inhibitors have been inferred from FT-IR spectra, UV–Vis spectra, surface morphological analysis and wide-angle X-ray diffraction studies.

Steel corrosion inhibition in acidic and alkaline medium by ethanolic extract of Milletia pinnata is described in this study. The inhibitive behavior of the inhibitor is evaluated by weight loss measurements, adsorption isotherms, and thermochemical parameters. The inhibitor exhibited a maximum of 87% and 90.5% inhibition efficiency against steel corrosion in 0.5 M NaOH and 1.0 M H2SO4, respectively. The weight loss linearly fit to Langmuir adsorption isotherm with correlation coefficient value close to unity. The thermochemical parameters indicated for predominant physical adsorption of the inhibitor molecules on the steel surface.

In this study, the effect of ‘natural/self cleaning’ of ground water by precipitation after a decade of tsunami is evaluated along the coast of Kanniyakumari district, Tamil Nadu, India. The samples were collected from five stations namely Colachel, Muttom, Periyakadu, Manakudy, and Kanniyakumari. The physicochemical parameters such as turbidity, total dissolved solids, electrical conductivity, pH, alkalinity, total hardness, calcium, magnesium, sodium, potassium, chloride, and fluoride were evaluated and compared with the database of the pre-tsunami sample collected in 2004. The results indicated that the ‘natural cleaning’ has improved the quality of the ground water over the years after tsunami.

For the first time, the homogeneous adsorption of ethanolic extract of Jacaranda mimosifolia green inhibitor is evaluated for inhibition of steel corrosion in acid environment. The inhibitive properties are evaluated by means of weight loss measurements, polarization studies, and electrochemical impedance spectroscopy. A maximum of 96% of inhibition efficiency is achieved by using 500 ppm of the green inhibitor. The mechanism and nature of adsorption of inhibitor on the surface of steel are evidenced by Langmuir adsorption isotherm and energy dispersive X-ray spectral elemental mapping.

Principal component analysis is a unique technique for reducing the dimensionality of the data. In this study, ten water quality parameters of the river Kaveri observed at five different stations of Tiruchirappalli for six years were collected and subjected to principal component analysis. A computational program was prepared in order to process and understand the data as a cluster. At first necessary data for compiling the program were listed and then fed to the program. Then the outputs were analyzed and possible linear and non-linear relationships between the water quality parameters and the timeline. It is understood that biological oxygen demand and fecal coli had a linear relationship. Further, the results suggested for group of factors that influence the water quality in a particular year.

For the first time, the homogeneous adsorption of a green inhibitor on the surface of steel was evidenced using energy dispersive X-ray spectral elemental mapping. Inhibition of steel corrosion in 1.0 M hydrochloric acid by Tabernaemontana divaricata plant extract and the evidences for adsorption of the inhibitor are described in this study. The inhibition characteristics of the green inhibitor were evaluated by means of weight loss and electrochemical measurements. A maximum of 95% inhibition efficiency was achieved by using 500 ppm of inhibitor. The adsorption of green inhibitor was found to obey the Langmuir's isotherm model. Further, the energy dispersive spectral mapping revealed the homogeneous distribution of the nitrogen, which indicated for the presence of inhibitor on the steel surface.

Electrospinning and post-spun conformations of hydrophobic poly(&alpha, amino acid)s are described in this study. The poly(&alpha, amino acid)s, poly(Gly), poly(L-Ala), poly(L-Val), and poly(L-Leu) were synthesized via corresponding N-carboxy-a-amino acid anhydrides. The average molecular weight and degree of polymerization of these polymers were determined by N-terminus labeling using 2,4-dinitrofluorobenzene and by viscometry in the case of poly(Gly). These poly(&alpha, amino acid)s were electrospun from trifluoroacetic acid or trifluoroacetic acid/dichloromethane solutions. The FT-IR spectroscopy and wide-angle X-ray diffraction indicated that the electrospun poly(L-Ala) and poly(L-Leu) fibers predominantly adopts &alpha, helical structure, whereas poly(L-Val) and poly(Gly) fibers exhibited mainly &beta, strand and random coil structures, respectively.

The spoilage of food is often observed by its odor rather than a change of its appearance. However, in the case of packed food, especially aqua foods, detection of such odor is impossible. The degree of spoilage is directly proportional to the quantities of chemicals released during the process. Based on this principle, researchers developed both invasive and non-invasive techniques for monitoring quality of aqua food. Naturally, humans prefer any information in visual format. Indeed, many of the inventions starting from telescopes to microscopes to infrared cameras are simple extensions of our visual senses. It is always preferable to transduce any complex data invisible than any other formats. In this view, recent progress in the development of halochromic sensors for evaluation of freshness/spoilage of aqua food is discussed.

Carbon nanofiber mats (CF) are potential materials for supercapacitors due to their unique properties such as high surface area, electrical conductivity, and chemical stability. In this study, CF prepared from new precursors, poly(acrylonitrile-co-crotonic acid) and poly(acrylonitrile-co-itaconic acid-co-crotonic acid) copolymers, were evaluated as substrates for supercapacitors. At first, the precursors were stabilized followed by carbonization. Then the carbon nanofiber mats were used as substrates for in situ polymerization of polyaniline. The electrochemical performances of polyaniline(PANi)/CF nanohybrids were analyzed by cyclic voltammetry and galvanostatic charge–discharge tests. The PANi/CFs exhibited a maximum specific capacitance of 113 F/g and showed better cyclic stabilities over 1000 cycles.

Highly uniform, flexible, and transparent electrodes based on in situ polymerization of PANi nanowires on nylon nanofiber-reinforced cellulose acetate thin film substrates were reported in this study. At first, the nylon nanofibers were electrospun followed by infiltration with cellulose acetate to get highly transparent substrate. Then PANi nanowires were grown uniformly on the transparent substrate by an in situ polymerization technique. The resulting thin films showed transparency from 39% to 82% and sheet resistivity between 188 and 8700 Ω/sq depending on the aniline monomer concentration. In addition, the transparent electrode exhibited outstanding toughness during bending cycles. Further, the transparent electrode showed excellent capacitive performance with specific capacitance of 402 F/g. These promising results highlight the importance of PANi nanowires and nylon reinforced cellulose acetate film as potential materials for optoelectronic devices.

A novel system for enhancing the mechanical properties of PVA/PAA cross-linked nanofibrous hybrid composites incorporating POSS was developed in this study. An electrospinning and followed by simple heat-treatment strategy was used to prepare nanofibrous PVA/PAA composite hydrogels. The mechanical properties have been dramatically improved by a heat-treatment as well as an incorporated nanohybrid POSS. The PVA/PAA composite nanofibers exhibited 2.3 times higher tensile strength and 4.4 times higher Young’s modulus after heat-treatment, suggesting that the elasticity of these nanofibers was reinforced by the formation of chemically cross-linked networks. Moreover, compared to the heat-treated PVA/PAA nanofibers without POSS, the PVA/PAA/POSS hybrid nanofibers (POSS content ∼0.6 wt.%) showed 3.3 times improvement in Young’s modulus and 2.0 times increase in tensile strength after heat-treatment at 160 °C for 30 min. This suggests that the elasticity of these nanofibers were dramatically reinforced by the incorporated POSS nanoparticles as well as chemically cross-linked networks via an ester bond formation between OH groups of PVA and COOH groups in PAA.

Development of an eco-friendly, reversible, and universal pH sensor based on electrospun cellulose nanofiber functionalized with a natural pigment is described in this study. A natural pigment from red cabbage has been extracted and incorporated onto the electrospun non-woven cellulose fibers by means of adsorption and chemical cross-linking techniques. The results revealed that the developed biocomposite is a universal pH sensor which is capable of detecting pH values in the range of 1–14 by indicating the unique color code against each pH. It was also found that the pH sensing was stable at different temperatures and at prolonged time. Moreover, the colors were reversible and the pH sensor was recyclable. Present study opens up new possibilities for using the developed universal pH sensor as a health monitor.

New precursors, poly(acrylonitrile-co-crotonic acid) (poly(AN-CA)) and poly(acrylonitrileco-itaconic acid-co-crotonic acid) (poly(AN-IA-CA)) copolymers, for the preparation of carbon fibers, were explored in this study. The effects of comonomers with acidic groups, such as crotonic acid (CA) and/or itaconic acid (IA), on the stabilization of nanofibrous polyacrylonitrile (PAN) copolymers were studied. The extent of stabilization, evaluated by Fourier transform infrared spectroscopy, revealed that the CA comonomer could retard/control the stabilization rate of PAN, in contrast to the IA comonomer, which accelerated the stabilization process. Moreover, the synthesized PAN copolymers containing CA possessed higher Mv than those of the IA copolymers and also showed outstanding dimension stability of nanofibers during the stabilization, which may be a useful property for improving the dimensional stability of polymer composites during manufacturing.

The annealing effects on thermodynamic properties and shape memory behaviors of the polycaprolactone (PCL) nanofiber filaments coated with silicone elastomer (Sylgard 184) were studied. The PCL nanofiber filaments were prepared from fiber mats having different thickness at different twist numbers via a twisting process. The thermodynamic and mechanical properties were remarkably enhanced by twist number as well as annealing process. Moreover, the Sylgard-coating has played a significant role to maintain the shape of each PCL nanofibers even above the melting point and to improve the toughness of the PCL nanofiber filaments.

A multipurpose chemical modification of cellulose to yield soluble cellulose derivatives was investigated on the basis of (i) O-acylation of the parent cellulose using N-Boc-protected Gly, αAla, and βAla, and subsequent Boc-removal, (ii) N-acylation of amino acid-modified cellulose in homogenous solution reaction system using Boc-oligopeptides with multiple types of the side-chain functionalities, and (iii) N-acylation of βAla-Cellulose using 10 kinds of simple Boc-oligopeptides. As for the (i), Thermochemical computation to estimate ΔG transition was well coincided with the observed yields in Oacylations. In the case of (ii), beside the similar ΔG-schemes, a strain energy profile, which is coupled with the preferred conformer transition of the amino acid-modified cellulose, was involved to rule out the N-acylation. The symmetric anhydrate in the N-acylating agents in the (iii) are tend to be in torsions due to the β-strand-like steric stabilizations in the peptides, resulting in the highest N-acylation yields as much as 98 %.

Although there have been a variety of methods developed in the recent years for the synthesis of silver nanoparticles, still there is a need for development of new shape-selective synthesis strategies. For the first time an extracellular biogenic synthesis technique is described for shape-controlled synthesis of perfectly cubic silver nanoparticles in this study. The abnormal intense (200) peak observed in X-ray diffraction pattern of the nanoparticles confirmed the formation of silver nanocubes. The knowledge obtained through this research opens up new opportunities for the use of fungi in the green synthesis of silver nanocubes.

The direct electrospinning of a non-derivatized cellulose (Cs)–chitosan (Ch) composite nanofiber is described for the first time. Either of two cellulose preparations from different sources, i.e., cotton (CsC) or bamboo (CsB), is fabricated into composite electrospun non-woven fabrics (ESNWs) with Ch using the trifluoroacetic acid–acetic acid mixed solvent. The total concentration of Cs + Ch in the mixed solvent is fixed at 4.0 wt.-% with various Cs/Ch weight ratios of 8:2, 5:5 (Figure shows CsB/Ch-ESNW), and 2:8, which are fabricated into fine fibers in the Cs/Ch-ESNWs having average diameters mostly

The chemical modification of cellulose (Cs)-chitosan (Ch)-electrospun non-woven (ESNW) composite fabrics is described. Since the as-spun Cs/Ch-composite ESNW (Cs : Ch = 4 : 6) deforms in water, an insolublilization procedure using an alkaline-ethanol solution was developed to extend the applications in an aqueous environment. The fine fiber surface was modified with bifunctional isocyanate in order to introduce the -NCO groups on the ESNW surfaces. The -NCO groups were condensed with N, N-(diethyl)ethylene diamine to generate a cationic diethylaminoethyl (DEAE)-ESNW. An enzyme, aminoacylase-I, was immobilized onto the cationic matrix under mild conditions. The immobilized enzyme was subjected to the stereo-specific recognition of Nα-acetyl-methionines. The results suggest that the chemically modified Cs/Ch-ESNW is a useful support matrix for biological catalysts.

A synthetic route is described here for novel peptide-cellulose conjugates containing O-phospho-l-serine. First, Boc-Ser(PO3Ph2) and the related dipeptides, Boc-Ser(PO3Ph2)-Asp(OBzl) and Boc-Asp(OBzl)-Ser(PO3Ph2), were synthesized by adopting the phosphoryl-protection strategy. The condensation reaction between the α-carboxyl group of the protected Boc-Ser(PO3Ph2) and the β-amino groups of β-Ala-Cellulose using isobutyl chloroformate and N-methylmorpholine yielded the product conjugate, N β-[Boc-Ser(PO3Ph2)]-β-Ala-Cellulose. The degree of substitution of Boc-Ser(PO3Ph2) towards the β-amino groups of β-Ala-Cellulose was estimated as DS N = 0.75 (maximum, 1.0). Similar reactions between β-Ala-Cellulose and two kinds of protected dipeptides, Boc-Asp(OBzl)-Ser(PO3Ph2) and Boc-Ser(PO3Ph2)-Asp(OBzl), gave the corresponding conjugates, and the DS N was estimated to be 0.95 and 0.69, respectively. The phenyl, benzyl, and Boc groups were removed in one-pot using the Pt2O catalyst in 50 % trifluoroacetic acid/acetic acid. The 31P-NMR and UV-Visible spectra indicated the complete deprotection without any observable elimination of the phosphorylated peptides.

The design and development of an economic and highly active non-precious electrocatalyst for methanol electrooxidation is challenging due to expensiveness of the precursors as well as processes and non-ecofriendliness. In this study, a facile preparation of core-shell-like NiCo2O4 decorated MWCNTs based on a dry synthesis technique was proposed. The synthesized NiCo2O4/MWCNTs were characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and selected area energy dispersive spectrum. The bimetal oxide nanoparticles with an average size of 6 ± 2 nm were homogeneously distributed onto the surface of the MWCNTs to form a core-shell-like nanostructure. The NiCo2O4/MWCNTs exhibited excellent electrocatalytic activity for the oxidation of methanol in an alkaline solution. The NiCo2O4/MWCNTs exhibited remarkably higher current density of 327 mA/cm2 and a lower onset potential of 0.128 V in 1.0 M KOH with as high as 5.0 M methanol. The impressive electrocatalytic activity of the NiCo2O4/MWCNTs is promising for development of direct methanol fuel cell based on non-Pt catalysts.

Biocontamination within the international space station is ever increasing mainly due to human activity. Control of microorganisms such as fungi and bacteria are important to maintain the well-being of the astronauts during long-term stay in space since the immune functions of astronauts are compromised under microgravity. For the first time control of the growth of an opportunistic pathogen, Aspergillus niger, under microgravity is studied in the presence of alpha-aminophosphonate chitosan. A low-shear modelled microgravity was used to mimic the conditions similar to space. The results indicated that the alpha-aminophosphonate chitosan inhibited the fungal growth significantly under microgravity. In addition, the inhibition mechanism of the modified chitosan was studied by UV-Visible spectroscopy and cyclic voltammetry. This work highlighted the role of a bio-based chitosan derivative to act as a disinfectant in space stations to remove fungal contaminants.